Why Are Your Doors Open?

I was getting a delivery, well before opening time (with hours posted), and a customer walked in behind the delivery guy, helping him push in the pallet of stuff. (It was an electric pallet jack, like the delivery guy needed help!) Looking up from my paperwork, I explained that we weren't open yet. The guy pleaded, I just want to look at some ______." I AGAIN explained that we weren't open yet, and told him when we opened. He responded, "If you aren't open then why are your doors open?" Hey genius, because we're getting a delivery! Like I'm going to let him in when I have large amounts of cash out of the safe and paperwork to finish and besides, the lights in the area he wanted to look at weren't even on yet!